Revenue from Contracts with Customers - Summary of Noninterest Income Disaggregated by Reportable Operating Segment and Revenue Stream (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		$ 43,416	$ 42,157	$ 33,246
Bank card and other fees		33,439	36,105	34,662
Mortgage banking, net		26,216	28,306	63,750
Insurance commissions		57,569	53,721	48,511
Wealth management		35,092	35,013	35,190
Other, net		11,187	9,842	6,551
Security gains (losses), net		39
Total Noninterest Income		206,958	205,144	221,910
Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		43,416	42,157	33,246
Bank card and other fees		30,444	31,521	30,935
Insurance commissions		57,569	53,721	48,511
Wealth management		35,092	35,013	35,190
Other, net		12,887	8,998	6,856
Total Noninterest Income		179,408	171,410	154,738
Not Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Bank card and other fees	[1]	2,995	4,584	3,727
Mortgage banking, net	[1]	26,216	28,306	63,750
Other, net	[1]	(1,700)	844	(305)
Security gains (losses), net	[1]	39
Total Noninterest Income	[1]	27,550	33,734	67,172
General Banking Segment [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		43,329	42,073	33,169
Bank card and other fees		33,382	36,058	34,624
Mortgage banking, net		26,216	28,306	63,750
Wealth management		838	639	48
Other, net		9,693	9,274	6,283
Security gains (losses), net		39
Total Noninterest Income		113,497	116,350	137,874
General Banking Segment [Member] | Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		43,329	42,073	33,169
Bank card and other fees		30,387	31,474	30,897
Wealth management		838	639	48
Other, net		11,769	8,469	6,621
Total Noninterest Income		86,323	82,655	70,735
General Banking Segment [Member] | Not Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Bank card and other fees	[1]	2,995	4,584	3,727
Mortgage banking, net	[1]	26,216	28,306	63,750
Other, net	[1]	(2,076)	805	(338)
Security gains (losses), net	[1]	39
Total Noninterest Income	[1]	27,174	33,695	67,139
Wealth Management Segment [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		87	84	77
Bank card and other fees		57	47	38
Wealth management		34,254	34,374	35,142
Other, net		538	567	163
Total Noninterest Income		34,936	35,072	35,420
Wealth Management Segment [Member] | Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		87	84	77
Bank card and other fees		57	47	38
Wealth management		34,254	34,374	35,142
Other, net		162	528	130
Total Noninterest Income		34,560	35,033	35,387
Wealth Management Segment [Member] | Not Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Other, net	[1]	376	39	33
Total Noninterest Income	[1]	376	39	33
Insurance Segment [Member]
Revenue From Contract With Customer [Line Items]
Insurance commissions		57,569	53,721	48,511
Other, net		956	1	105
Total Noninterest Income		58,525	53,722	48,616
Insurance Segment [Member] | Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Insurance commissions		57,569	53,721	48,511
Other, net		956	1	105
Total Noninterest Income		58,525	53,722	48,616
Insurance Segment [Member] | Not Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Total Noninterest Income	[1]	$ 0	$ 0	$ 0

[1] Noninterest income not in scope for FASB ASC Topic 606 includes customer derivatives revenue and miscellaneous credit card income within bank card and other fees; mortgage banking, net; amortization of tax credits, accretion of the FDIC indemnification asset, cash surrender value on various life insurance policies, earnings on Trustmark’s non-qualified deferred compensation plans, other partnership investments and rental income within other, net; and securities gains (losses), net.